Pneumatic unit for player pianos



R. s. HOYT Filed 0st. 1, 1921 liwenio r. ieubemSJibyiZ Patented Feb. 17,1925.

UNITED STATES REUBEN S. HOYT, OF ALEXANDRIA, NEW HAMPSHIRE.

PNEULMA'IIC UNIT FOR PLAYER PIANOS.

Application filed October 1, 1921.

To all whom it may concern:

Be it known that I, REUBEN Hora, a citizen of the United States ofAmerica, and a resident of Alexandria, in the county of Grafton andState of New Hampshire, have invented certain new and usefulImprovements in Pneumatic Units for Player Pia-nos, of which thefollowing is a specification.

This invention relates to pneumatic units for player pianos and has forits object the provision of a device of this character in which aprimary bellows is utilized to control the operation of the valvecontrolling the passage of air from the secondary or power bellows.

Another object of the invent-ion is the provision of means forregulating the amount of air admitted to the unit according to itslocation in the piano relatively to the tracker board.

A further object is the production of a device of this character whichwill be sim ple in construction, inexpensive to manufacture, effectivein operation and in which all necessary adjustments of the variousvalves may be made exteriorly of said unit.

The invention consists primarily of a unit having a primaryvalve-controlling bellows secured to an outer face thereof.

The invention further consists of a unithaving secured to its upper facea primary bellows provided with an arm articulated to the valvecontrolling the air passage from the secondary or power bellows.

The invention further consists in a unit having a vent hole providedwith a valve by which the amount of air passing through said vent may beregulated to suit various conditions.

The invention further consists in certain novel features of constructionand arrangement of parts which will be understood readily by referenceto the description of the drawings and to the claims to be hereinaftergiven.

For the purpose of illustrating the invention, one preferred formthereof is illustrated in the drawings, this form having been found togive satisfactory and reliable results although it is to be understoodthat the various instrumentalities of which the invention consists canbe variously arranged and organized and the invention is not limited tothe precise arrangement and organi- Serial No. 504,626.

zation of these instrumentalities as herein shown and described exceptas required by the scope of the appended claims.

Of the drawings:

Figure 1 represents an elevation of a pneumatic unit embodying theprinciples of the present invention.

' Figure 2 represents a vertical section of the same the cutting planebeing on line 2, 2, on Fig. 3.

Figure 3 represents a plan of the same.

Figure 4 represents a horizontal section of same on line 4, 4, on Fig.2, and

Figure 5 represents a transverse vertical section of same on line 5, 5,on Fig. 3.

Similar characters indicate like parts throughout the several figures ofthe drawlngs.

In the drawings, 10 is a block, preferably U-shaped, and provided with acover plate 11 secured thereto.

This cover plate 11 is provided with a port 12 and superimposed uponsaid plate are two separated blocks 13 and 14.

Superimposed upon these blocks 13 and 14 is another plate 15 having aport 16 therein alined with the port 12.

Between the plates 11 and 15 is a narrow strip 17 forming a bearing fora valve stem 18, this valve stem being threaded and having adjustablymounted thereon the lower valve 19 and the upper valve 20.

The valve stem 18 is free to move through the bearing in the strip 17and the valves 19 and 20 may be adjusted on the valve stem 18 to varythe distance between the same.

Threaded to the upper end of the valve stem 19 is a head 21.

Between the head 21 and the valve 20 is positioned the outer end of anarm 22 secured by screws 23 to a primary bellows 24 which normally ispartially deflated.

This primary bellows 24 is secured to the upper plate 15 and has apassage 25 therefrom communicating through an opening 26 with acompartment 27 formed in the block 14 and between the upper and lowerplates, 15 and 1.1.

Extending upwardly from the compartment 27 is a tubular member 28adapted to be inserted into one end of a tube 29 leading to an openingin the usual tracker board of a player piano.

Extending from one end of the block 10 is a tubular member 30 adapted tobe inserted plate 11 and communicates with the air space 34.

'Secured to the block-10 is a power bellows: or pneumatic 36 havingsecured to one end thereof a projection member 37 adapted to communicatewith and actuate a vertical. rod for operating the hammer of. the pianoaction. Theopposite end of the power bellows 36 ishinged at 40. 7

Normally the Valve 20 is separated from the upper face of the plate 15thereby permitting air to, enter through the port 16 and fill the airspace 34,tubular member 35 and the power bellows 36, it being understoodthat at this time thevalve19 is firmly held, against the under faceof'the' plate 11 thereby closing the port 12.

The power bellows36 isof usual construction having an upper fixed plate41 and a lower movable plate, 42, these two plates 41 and 42 beingcoiinected together by flexible side: and end. walls;43, preferably ofrubber.

From the vacuum. chamber 33 extends a vent 44 through one end of theblock 10, this vent 44 being provided with an up Wardly extending branch45.

Positioned in the plates 11 and- 15 and extending downwardly into theblock 10 is a cylindrical member- 46, said member being in alinementwith, the vertical vent passage 45.

This cylindrical; member is providedi with a port 47communicatingwiththe compartment 27 between the plates ll and 15.

Disposed within the cylindrical member 46 is a removable plug 48 havinga passage 49 extending upwardly therein from the upper end of the ventpassage 45.

The upper end of this passage 49 has extending radially therefrom apassage 50 the outer end of which normally registers with the port 47.

1 The block 48 is frictionally held in position but may be rotated aboutits, axis in order to close the port 47 or vary the degree of itsopening.

This provides a ready means of varying the opening of said port 47 fordifferent pneumatics according to their position in the piano relativelyto the Vacuum chest and tracker board.

It has been found in practice that each pneumatic unit requires adifferent adjustment and; by means ofthe construction herein shown, thisdesired adjustment is made possible.

By removing. the. plug, 48, the vent passage 45 and horizontal vent 44may be readilycleared:ofdust-or any other obstructions.

This is of considerable importance as devices of this class are very aptto become inoperative by dust accumulating in the vent and clogging thesame.

It is obvious, therefore, that itis quite desirable toprovide means forreadily cleaning out the passages without disturbing the variousoperating parts.

Ordinarily in devices of this character the operating parts are mostlyconfinedwithin the pneumatic unitand are not readily accessible foradjustment or the replacing ofworn parts.

In the present device all of the adjustments may. be made on the outsideof the block which obviously is a, great advantage.

The operation of'the device is as follows:

A unit is provided for each string of the piano and these various unitsare mounted upon a support in such a position that the member 37'mayactuate a. hammer-actuating rod forming a part ofthe piano action.

When thus mounted, the various units are then connected by means of thetube 29 to the tracker-board and the pipe 31 to the vacuum chest.

With the units thus connected to the vacuum chest andtracker board,shouldv an opening in the tracker board, he uncovered or exposed, airwill be admitted to the tube 29 and pass through the compartment 27,opening 26, passage 25 into. the primary bellows 24;

The bellows 24 will; thereby be expanded and the arm 22 secured theretowill permit the valve 20- to be moved downwardly by the atmosphericpressure and close the port 16 at the same time causing the valve 19 tobe moved downwardly and open the port 12. g

As a consequence of this movementof the valves 19 and 20, acommunication from the vacuum chest is made through the tubular member30, vacuum chamber 33, port 12, air space 34, tubular member 35, to theinterior of the pneumatic power bellows 36 secured to the lower portionof the block 10.

The suction through these passages and chambers will thereupon cause thepower bellows 36 tov be collapsed and the projection 37 on the rear endof the movable plate 42 will be consequently moved upwardly to actuatethe hammer of the pneumatic action. 7

When the tracker board is again covered, the pneumatic or power bellows36- returns to its normal position, the air within the primary bellows24 being withdrawn through the passage 25, opening 26, compartment 27,port ll, passages 50, 49 and 45, and vent 44, into the air chamber 33and therefrom through the tubular member 30 and pipe 31.

When the air is thus withdrawn from the primary bellows 24, the arm 22acting upon the head 21 of the valve stem 18 will lift said valve stemand cause the valve 19 to close the port 12 and the valve 20 to open theport 16.

This opening of the valve 16 will permit the air to pass again into theair space 3st and through the tubular member 35 into the power bellows-36 and again expand the same.

By the expansion of the power bellows 36, the plate 37 will be returnedto its lowermost position as indicated in Fig. 2 of the drawingspreparatory to another operation thereof.

With the parts in the position indicated in Fig. 2 of the drawings, theinterior of the primary bellows 24 is in communication with the vacuumchamber 33 and all air is therefore withdrawn therefrom and remainswithdrawn until an opening in the tracker board is uncovered and permitsair to enter said primary bellows and expand the same.

This expansion of the primary bellows causes the arm 22 to move awayfrom the head 21 on valve stem 18 and the atmosphere will then act uponthe valve 20 forcing it to its seat and at the same time forcing thevalve 19 away from its seat and uncovering the port 12.

It is self-evident therefore that the pri mary bellows 24:, while beingdeflated, will lift the valves 19, 20 and while being filled with airthe arm 22 will be moved into position to permit the valves 19, 20 to belowered by the pressure of the atmosphere thereon.

This makes a very simple construction of unit in which all the necessaryadjustments may be made without removing the unit from the support onwhich it is mounted.

By making all adjustments on the outside of the unit the operating partsmay be readily regulated and tested in order to secure perfect results.

The plug 48 can be adjusted to make the vent passage of any size neededfor the proper operation of the primary bellows 24 and can be entirelyclosed for testing said primary bellows.

By the method of operation herein shown and described, the pneumatic isquicker to act and a greater volume of tone is attained.

It is believed that the operation and many advantages of the inventionwill be understood without further description.

Having thus described my invention, I claim:

1. A pneumatic unit provided with a power bellows; a vacuum chamber; apipe leading therefrom to the vacuum chest; an air space communicatingwith said power bellows and having ports to said chamber and toatmosphere; a primary bellows secured to the top of said unit andCOPHIlLlDieating by a tube with an opening in the tracker board; valvesto close said ports; a valve stem projecting beyond the upper face ofsaid unit and on which said valves are mounted; a head on the other endof said stem; and an arm on said primary bellows coacting with said headto move said valves.

2. A pneumatic unit provided with a power bellows; a primary bellowscommunicating by a passage with an opening in the tracker board; avacuum chamber having a vent therefrom communicating with the passage tosaid primary bellows; a pipe leading from said chamber to the vacuumchest; an air space communicating with said power bellows and havingports to said vacuum chamber and to atmosphere; valves adapted to beactuated by said primary bellows to alternately close said ports; and avalve in said vent.

3. A pneumatic unit provided with a power bellows; a vacuum chamberhaving a vent; a pipe leading from said chamber to the vacuum chest; anair space communicating with said power bellows and having ports to saidvacuum chamber and to atmosphere; a primary bellows communicating by atube with an opening in the tracker board; valves adapted to be actuatedby said primary bellows to alternately close said ports; a cylindricalmember in said vent having a port communicating with the passage to saidprimary bellows; and a plug rotatable in said member and having apassage therein from said vent to the port in said member.

4. A pneumatic unit provided with a power bellows and valves underatmospheric pressure for controlling the operation of said bellows,combined with a primary bellows; an arm thereon adapted to lift saidvalves against said atmospheric pressure; means connected with thevacuum chest of a player piano for creating a vacuum in said primarybellows; a regulating valve in said connecting means; and meansconnected with the tracker board of said piano for inflating saidprimary bellows and moving said arm to permit said valves to be loweredby the atmospheric pressure thereon.

5. A pneumatic unit provided with a power bellows; a vacuum chamber; anair space having ports to the vacuum chamber and to atmosphere; alinedvalves for closing said ports; a primary bellows, the outer face ofwhich is exposed to atmospheric pressure; and means interposed betweensaid valves and primary bellows whereby said valve during the deflationof said primary bellows will be inoved to closethe pert between Signedby me atBoston, Mase, this 29th the va cuum chamber and air space,anduppn day of September, 1921; the expansion of said p imary bellowswill permitthej valves to be moved in the oppo- REUBEN S. HOY-T. sitedirection, independently of saiidj pri WVitnesses:

mary be11oWs, by the atmospheric PlQSSure WALTER E. LOMBARD,

aetingvthereon. v NATHAN C. LOMBARD.

